From Stephen Hawking to Matrix: Making Science Fiction Come True (1)

Whether it’s science fiction novels or the Matrix trilogy, to “go anywhere with thoughts like a butterfly” or even to attain immortality has long been mankind’s dream. But from a neuroscience and neural engineering perspective, we are still far from this goal, the reason being our knowledge about the human brain, signal transmission and, especially, information coding technologies are rather limited.

The Significance of Brain-Computer Interface (BCI) Technologies

There is a famous memoir titled Le Scaphandre et le Papillon, whose author is Jean Dominique Bauby, the editor-in-chief of French ELLE magazine. One day Bauby woke in his bed and found he couldn’t move his body or make a sound. All he could do was to blink his left eye. Language therapist Henriette was taking care of him. When Bauby wants to thank her, he needs to blink his eyes five times while Henriette reads him the French alphabet so that he could spell out the French word Merci. Bauby suffered a sudden stroke and lapsed into a coma. He was physically paralysed with what is known as locked-in syndrome. Blinking his left eye is his only way of communicating with the world, but his brain and mental activities are fully functional. One can only imagine his loneliness and despair. Miraculously, by blinking his left eye Bauby completed his memoir Le Scaphandre et le Papillon, the film adaption of which won many awards. This is why BCI technologies can be tremendously useful. One day patients like Bauby will no longer have to like in a diving bell. They will be able to communicate with the world freely through neural activities, and their thoughts can break free of their bodies’ limits and fly like butterflies.

How Brain Wave Works

Brain wave electrical signal is caused by the electrophysiological activities of the brain’s nervous tissue on the cerebral cortex. Therefore, to better understand how the brain wave works, it will be beneficial to first understand the brain’s anatomy. The cerebral cortex, also known as the cerebral mantle takes up a third of the brain. It is mainly responsible for cognition and emotions. The cerebral cortex is divided by three longitudinal fissures into five parts: frontal lobe, parietal lobe, temporal lobe, occipital lobe and cerebellum.

The frontal lobe is located in the front of the brain. It is mainly responsible for concentration and short-term memory. To the front of the occipital lobe is the parietal lobe, which is responsible for sensory information, e.g. touch, spatial awareness, etc. Underneath the lateral sulcus of the cerebral hemisphere is the temporal lobe, which is responsible for processing information, e.g. sight, hearing, etc. and plays an important role in long-term memory. The occipital lobe is located in the back of the cranium and functions as a visual processing centre. The insula lobe is folded deep within the lateral sulcus. Research has shown that it is related to not only emotions and awareness but also motor control, self-awareness, interpersonal relationship, etc. At the same time, mental illnesses have also been found to be related to the insula lobe.

Electrical signals during brain activities can be recorded in EEG, which reflects the totality of the activities of nerve cells. The electric signal produced by one single nerve cell is rather weak. Therefore, the cerebral cortex can generate brain waves of different frequencies. The characteristics of these electric activities reflect the different statuses of the brain.

The electrical activities of the cerebral cortex include spontaneous activities and induced activities. Spontaneous electric activities are caused by people’s different emotional states and correspond to different brain wave patterns, while induced electric activities are caused by external triggers.

The Birth of BCI Technologies

Scientific research into BCI dates back to 1963. Doctor Grey Walter of Burden Neurological Institute in the UK used the latest EEG technology of the time to play a joke on his patients. These patients who were suffering from epilepsy had electrodes placed in their brains close to the cerebral cortex to determine the location of their illness by monitoring their nervous activities. Since the electrodes are relatively large, the record resistance is low. Although the electrical activities of a single nervous cell couldn’t be recorded, the field potentials of the collective activities of nervous cells around the electrodes could. These patients will wear the electrodes for a week or two in the hospital. Once on a whim, Dr. Walter secretly connected these electrodes to a field potential converter while the patients were watching landscape photo slides. This field potential converter could use the field potential signals of the motor cortex of a patient’s brain to control the projector. Then a miracle happened: Every time a patient was about to change slides, the projector knows his mind before he put his hand on the button. This is the first time BCI technology happened in the real world. Brain nerve signals were collected and converted into electrical signals to control external devices.

This experiment was truly ahead of its time. Before, such technologies had only appeared in science fiction movies. What lay behind this joke was Doctor Walter’s exploration into the deepest secrets of the brain. He discovered that the electrical activities of the brain are related to brain activities such as attention and expectation. Prior to this, brain electrical activities only referred to the rhythmic fluctuations (Alpha Waves) that happen ten times every second. Through these fluctuations, people could deduce the brain is at a state of alarm but not predict any specific thoughts. Doctor Walter is an excellent engineer. He used multiple averaging and denoising technologies to obtain the purest brain waveform since the invention of EEG: Event-Related Potential (ERP). Since then, scientists have used ERP to conduct quantitive research on not only how the brain reacts to external visual and audio stimuli, but also the cognitive process of the brain. And a new window to brain research has been opened.